The game of Blackjack is commonly played in casinos worldwide. In a casino, the game of Blackjack involves a dealer and one or more players who play against cards dealt the dealer.
Another rule, basic to the game, is that each player attempts to draw cards until the sum of the cards are as close to twenty-one as possible, without exceeding twenty-one. Whenever the sum of the cards in a single hand exceeds twenty-one, the player or dealer, holding the cards loses.
Cards are dealt to each player, including the dealer, with at least one card (the "hole" card) down. To speed play, when the dealer shows a card which is a member of a blackjack pair of cards, the hole card is commonly privately perused by the dealer to see if the hole card is the other member of the blackjack pair. If the hole card is the other member of the blackjack pair, play stops and the dealer wins.
Those skilled in the art of Blackjack understand that statistics play a very important part in winning or losing. Numbers of methods have been conceived through the years for integrating knowledge of cards played into a scheme which determines the magnitude of a bet, or whether another card should be taken. Equally as important, when a player is making a decision about whether or not to ask for another card, is a knowledge of the value of the dealers hole card, especially when the showing card is a face card.
For an unscrupulous dealer, who has a player as an accomplice, a look at the hole card, to determine whether or not the dealer's cards comprise a blackjack, provides an opportunity to determine the value of the hole card. With a knowledge of the value of the hole card, the unethical dealer is able to signal the player accomplice the relative value of the card in a manner which is subtle and generally undetectable by casino management. With that knowledge, the accomplice makes a more knowledgeable decision concerning requesting or declining being hit with another card and thereby significantly tilts the odds of winning away from the casino.